The present invention relates generally to devices for changing the aiming of automotive headlamps, and relates more specifically to devices for directing an automotive headlamp reflector to a desired position and for indicating any variations of the actual position of the automotive headlamp reflector from the desired position, as set at the factory.
Modern day headlamps for vehicles have been engineered and designed to be aerodynamically efficient. In this regard, the headlamps are designed as sealed assemblies wherein the portion of the headlamp approximate the outer surface of the automobile is relatively stationary, and is aerodynamic. A headlamp assembly normally includes: a fixed housing, to which an outer headlamp lens is affixed; a movable reflector, which is mounted within the fixed housing; and a stationary headlamp bulb, which is positioned within the movable reflector. Typically, the movable reflector is mounted to the housing by a number of universal or ball-type pivots which are stationary, or fixed, on the housing. A first pivot point and adjustor mechanism is generally disposed vertical of the fixed pivot, and a second pivot point and adjustor mechanism is generally disposed horizontal of the fixed pivot. As such, the movable reflector may be pivoted about the fixed pivot in the vertical and horizontal planes to aim the headlamp beam. The first and second pivot points, normally termed the vertical pivot and the horizontal pivot, are typically provided by mechanical adjustor mechanisms which effect movement of the reflector in the horizontal and vertical planes. These adjustor mechanisms normally employ an adjustor screw, or other similar component, to effect linear movement. The adjustor mechanisms are typically mounted to the housing of the headlamp assembly and are typically operatively connected to the movable reflector by ball and socket type pivots, or the like, such that linear movement of the adjustor screw will produce pivoting of the removable reflector in the horizontal and vertical planes. In this manner, the adjustor mechanisms can be used to adjust the aim of automobile headlamp beams.
Before an automobile is released to the consumer, the movable reflectors of the headlamp assemblies are adjusted to a desired position so that the headlamp beams are properly aimed in both the vertical and horizontal directions. To this end, adjustor mechanisms are normally operated at the automobile assembly plant.
Once proper vertical and horizontal aiming of the headlamps are attained and before the automobile is released to the consumer, vertical and horizontal indicators on each adjustor mechanism are manipulated to provide a visual indication that each movable reflector is in the desired, or "zero", position. The indicators either naturally transmit, or are adjusted in some manner in order to transmit, a visual indication of the zero position. Thereafter, if a movable reflector moves from its desired position, due, for example, to vibration, jarring, or the vehicle being in an accident, a mechanic can use the visual indication to determine that the movable reflector is no longer in its desired position. Then, the mechanic can operate the adjustor mechanisms in order to return the horizontal and vertical indicators to the zero positions, which should properly align the reflector.
The Department of Transportation of the United States Government has set forth specific guidelines dealing with vehicle headlamp aiming and indicating mechanisms in both the horizontal and vertical directions. These guidelines have been issued under regulation FMVSS 108, and relevant portions of these guidelines are set forth briefly hereinafter, wherein the degree of accuracy required of the horizontal and vertical indicators is apparent. The relevant portions of the regulation state as follows:
On-vehicle aiming.
Each headlamp system that is capable of being aimed by equipment installed on the vehicle shall include a Vehicle Headlamp Aiming Device (VHAD) that conforms to the following requirements:
(a) Aim. PA2 The VHAD shall provide for headlamp aim inspection and adjustment in both the vertical and horizontal axes.
(1) Vertical aim: PA3 The VHAD shall include the necessary references and scales relative to the horizontal plane to assure correct vertical aim for photometry and aiming purposes. An offvehicle measurement of the angle of the plane of the ground is permitted. In addition, an equal number of graduation form the "O" position representing angular changes in the axis in the upward and downward directions shall be provided. PA4 (I) Each graduation shall represent a change in the vertical position of the mechanical axis not larger than 0.19 degree (1 in. At 25 ft.) to provide for variations in aim at least 1.2 degrees above and below the horizontal, and have an accuracy relative to the zero mark of less than 0.1 degree. PA3 (2) Horizontal aim. PA3 The VHAD shall include references and scales relative to the longitudinal axis of the vehicle necessary to assure correct horizontal aim for photometry and aiming purposes.
An "O" mark shall be used to indicate alignment of the headlamps relative to the longitudinal axis of the vehicle. In addition, an equal number of graduations from the "O" position representing equal angular changes in the axis relative to the vehicle axis shall be provided. PA4 (I) Each graduation shall represent a change in the horizontal position of the mechanical axis not greater than 0.38 degree (2 in. at 25 ft.) to provide for variations in aim at least 0.76 degree (4 in. at 25 ft.) to the left and right of the longitudinal axis of the vehicle, and shall have an accuracy relative to the zero mark of less than 0.1 degree.
With regard to the vertical aiming indicator, a popular form of indicator in the industry is a spirit or bubble level which is mounted to the movable reflector component of the headlamp assembly and is viewable through the lens or an opening in the stationary headlamp housing. The mounting of the bubble level is typically adjustable so that once the desired zero vertical positioning of the headlamp is attained, the bubble level can be "zeroed out", that is, adjusted so that the bubble is at the zero indicia. As such, any subsequent movement of the movable reflector from the desired vertical position will produce a movement in the bubble. Consequently, a mechanic will have an immediate visual indication that the vertical aiming of the headlamp is out of adjustment.
While a bubble level can operate and provide sufficient indication in the vertical plane, it can be appreciated that a bubble level cannot provide an indication in the horizontal plane. Therefore, the industry has developed a number of different types of horizontal adjusting and indicating mechanisms for use with movable reflectors. For example, U.S. Pat. No. 5,091,829 discloses a horizontal adjusting and indicating mechanism wherein an adjusting wheel is affixed to a threaded shaft such that turning the adjusting wheel rotates the threaded shaft. The rotation of the threaded shaft causes a headlamp reflector to move. Because the adjusting wheel is meshed with a toothed wheel, rotating the adjusting wheel also causes the toothed wheel to rotate. The toothed wheel is provided with a scale which cooperates with a pointer to indicate, in effect, the positioning of the headlamp reflector. In order to provide that the scale on the toothed wheel correctly indicates the desired positioning of the automotive headlamp reflector, the adjusting mechanism provides that the toothed wheel can be disengaged from the adjusting wheel, turned to the "zero" position , and then re-meshed with the adjusting wheel. As a result, the ability of the scale on the toothed wheel to precisely indicate the zero position of the automotive headlamp reflector is limited by the meshability of the toothed wheel and the adjusting wheel when the toothed wheel has been turned to its zero position. Additionally, the fact that the toothed wheel must be brought out of mesh with the adjusting wheel after the reflector is moved to the desired location provides that the toothed wheel becomes a loose part. Therefore, the toothed wheel is subject to, for example, breaking upon re-engagement with the adjusting wheel. Furthermore, because the toothed wheel and adjusting wheel are not coaxial, the adjusting mechanism disclosed in U.S. Pat. No. 5,091,829 is not extremely compact or accurate within the guidelines noted above.
Other horizontal indicators in the prior art suffer from similar disadvantages such as not meeting the required governmental standards for accuracy.
The difficulties discussed hereinabove are substantially eliminated by the present invention.